Support columns are used for height adjustable chairs and tables. Such a support column comprises a foot structure and a stand tube. A gas spring is received by the stand tube. The cylinder of the gas spring is guided within an upper end portion of the stand tube, and the lower end of the piston rod is connected to the bottom of the stand tube. A seat plate is connected to the upper end of the cylinder of the gas spring. The cylinder of the gas spring is slidingly guided in a guide unit inserted into the upper end portion of the stand tube.